Continuous production of polymethylpentene membranes

Abstract

Gas separation membranes may be prepared in a continuous manner by passing a porous support which may, if so desired, be backed by a fabric through a solution of polymethylpentene dissolved in an organic solvent such as hexane. The support member is passed through the solution while one side thereof is in contact with a roller, thereby permitting only one side of the support member to be coated with the polymer. After continuously withdrawing the support member from the bath, the solvent is allowed to evaporate and the resulting membrane is recovered.

We claim as our invention: 
     
       1. A process for the continuous production of a polymethylpentene membrane which comprises dissolving said polymethylpentene in an organic solvent, placing the resultant solution in a container, continuously passing a microporous support into said container and through and in direct contact with said solution, said support being in contact on one side thereof with a moving roller whereby only one side of said support is in contact with said solution, transferring polymethylpentene from said solution to said one side of the support, continuously withdrawing the resulting polymer-coated support from said container, evaporating said solvent and continuously recovering the resultant polymethylpentene membrane. 
     
     
       2. The process as set forth in claim 1 further characterized in that said porous support is backed by a fabric. 
     
     
       3. The process as set forth in claim 2 in which said fabric is a polyester. 
     
     
       4. The process as set forth in claim 2 in which said fabric is a nylon. 
     
     
       5. The process as set forth in claim 1 in which said polymethylpentene is present in said solution in an amount in the range of from about 0.5 to about 5% by weight of said solution. 
     
     
       6. The process as set forth in claim 1 in which said organic solvent comprises a paraffinic hydrocarbon. 
     
     
       7. The process as set forth in claim 6 in which said solvent is n-pentane. 
     
     
       8. The process as set forth in claim 6 in which said solvent is n-hexane. 
     
     
       9. The process as set forth in claim 6 in which said solvent is n-heptane. 
     
     
       10. The process as set forth in claim 1 in which the thickness of said polymethylpentene membrane is in a range of from about 3,000 Angstroms to about 12,000 Angstroms.